Nitration of aromatic nucleus is one of the most basic reactions in organic chemistry and is widely used for preparing nitro aromatic compounds. However, the reaction is notorious for several reasons and most pharmaceutical manufacturers are discouraged to carry out large scale nitration in-house. Safety issues are the primary concerns. Two major factors contribute to the safety aspect of the reaction. The first is the reaction itself. The most commonly used nitrating reagent is a mixture of concentrated nitric acid and sulfuric acid. Both of them are strong oxidizers. Although there are alternative nitrating reagents, the majority of them generate nitric acid or other highly reactive intermediates in situ. The nitration reaction is usually highly exothermic and has high risk of runaway to explosion upon mishandling of the process or equipment failures. The second is the nitrated products. Most of them have low thermo and/or impact stabilities and release large quantity of energy upon decomposition (for instance, TNT, trinitrotoluene, is a powerful explosive). As a result, extra precautions have to be taken when nitration is carried out, which include special equipment (e.g. bunkered reactors) and intensive training of personnel. Besides safety problems, side reactions are another concern. For instance, over-nitration could occur whenever the nitrating reagents are overcharged. Regioisomer formation and reactions at side-chains are common. Therefore, the development of new nitration methods that lead to safer nitration processes and better control of chemistry is still an important research goal.